The present disclosure generally relates to electrical power supplies and, more particularly, to miniaturized energy harvesting and storage.
Conventional electro-chemical batteries are often used in powering sensor electronics, for example, in components for wireless communication. Their finite power capacity thus may become a major limitation in deploying sensor electronics with conventional batteries in the field for prolonged unattended operations. Therefore, there has been an increasing demand for harvesting electrical energy from ambient vibrations in the surrounding environment using electromechanical transducers based on electromagnetic, electrostatic, or piezoelectric effects. Among these transducers, piezoelectric power generators are the most applicable to miniaturized sensors because of their great potential in achieving high power densities using novel nano-scale materials and structures. The current technology is limited to a handful of nanostructures made of piezoelectric materials such as ZnO (zinc oxide) with potential output power densities of about 80 milliwatts per square meter (mW/m2). Requirements for future systems may dictate higher power densities beyond these values for powering miniaturized (e.g., having a volume less than one cubic millimeter) sensors.